net: phy: add helpers for comparing phy IDs

There are several places which open code comparing PHY IDs. Provide a
couple of helpers to assist with this, using a slightly simpler test
than the original:

- phy_id_compare() compares two arbitary PHY IDs and a mask of the
significant bits in the ID.
- phydev_id_compare() compares the bound phydev with the specified
PHY ID, using the bound driver's mask.

Signed-off-by: Russell King <[e-mail]>
Reviewed-by: Simon Horman <[e-mail]>
Reviewed-by: Andrew Lunn <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/phy/micrel.c

···
 {
 	int ret;
 
-	if ((phydev->phy_id & MICREL_PHY_ID_MASK) != PHY_ID_KSZ8051)
+	if (!phy_id_compare(phydev->phy_id, PHY_ID_KSZ8051, MICREL_PHY_ID_MASK))
 		return 0;
 
 	ret = phy_read(phydev, MII_BMSR);
···
 	 *
 	 * distance to fault = (VCT_DATA - 22) * 4 / cable propagation velocity
 	 */
-	if ((phydev->phy_id & MICREL_PHY_ID_MASK) == PHY_ID_KSZ9131)
+	if (phydev_id_compare(phydev, PHY_ID_KSZ9131))
 		dt = clamp(dt - 22, 0, 255);
 
 	return (dt * 400) / 10;
···
 	 */
 	dt = FIELD_GET(data_mask, status);
 
-	if ((phydev->phy_id & MICREL_PHY_ID_MASK) == PHY_ID_LAN8814)
+	if (phydev_id_compare(phydev, PHY_ID_LAN8814))
 		return ((dt - 22) * 800) / 10;
 	else
 		return (dt * 400) / 10;

drivers/net/phy/phy_device.c

···
 		fixup = list_entry(pos, struct phy_fixup, list);
 
 		if ((!strcmp(fixup->bus_id, bus_id)) &&
-		    ((fixup->phy_uid & phy_uid_mask) ==
-		     (phy_uid & phy_uid_mask))) {
+		    phy_id_compare(fixup->phy_uid, phy_uid, phy_uid_mask)) {
 			list_del(&fixup->list);
 			kfree(fixup);
 			ret = 0;
···
 		if (strcmp(fixup->bus_id, PHY_ANY_ID) != 0)
 			return 0;
 
-	if ((fixup->phy_uid & fixup->phy_uid_mask) !=
-	    (phydev->phy_id & fixup->phy_uid_mask))
+	if (!phy_id_compare(phydev->phy_id, fixup->phy_uid,
+			    fixup->phy_uid_mask))
 		if (fixup->phy_uid != PHY_ANY_UID)
 			return 0;
 
···
 			if (phydev->c45_ids.device_ids[i] == 0xffffffff)
 				continue;
 
-			if ((phydrv->phy_id & phydrv->phy_id_mask) ==
-			    (phydev->c45_ids.device_ids[i] &
-			     phydrv->phy_id_mask))
+			if (phy_id_compare(phydev->c45_ids.device_ids[i],
+					   phydrv->phy_id, phydrv->phy_id_mask))
 				return 1;
 		}
 		return 0;
 	} else {
-		return (phydrv->phy_id & phydrv->phy_id_mask) ==
-			(phydev->phy_id & phydrv->phy_id_mask);
+		return phy_id_compare(phydev->phy_id, phydrv->phy_id,
+				      phydrv->phy_id_mask);
 	}
 }
 

drivers/net/phy/phylink.c

···
  */
 static bool phylink_phy_no_inband(struct phy_device *phy)
 {
-	return phy->is_c45 &&
-		(phy->c45_ids.device_ids[1] & 0xfffffff0) == 0xae025150;
+	return phy->is_c45 && phy_id_compare(phy->c45_ids.device_ids[1],
+					     0xae025150, 0xfffffff0);
 }
 
 static int phylink_sfp_connect_phy(void *upstream, struct phy_device *phy)

include/linux/phy.h

···
 #define PHY_ID_MATCH_MODEL(id) .phy_id = (id), .phy_id_mask = GENMASK(31, 4)
 #define PHY_ID_MATCH_VENDOR(id) .phy_id = (id), .phy_id_mask = GENMASK(31, 10)
 
+/**
+ * phy_id_compare - compare @id1 with @id2 taking account of @mask
+ * @id1: first PHY ID
+ * @id2: second PHY ID
+ * @mask: the PHY ID mask, set bits are significant in matching
+ *
+ * Return true if the bits from @id1 and @id2 specified by @mask match.
+ * This uses an equivalent test to (@id & @mask) == (@phy_id & @mask).
+ */
+static inline bool phy_id_compare(u32 id1, u32 id2, u32 mask)
+{
+	return !((id1 ^ id2) & mask);
+}
+
+/**
+ * phydev_id_compare - compare @id with the PHY's Clause 22 ID
+ * @phydev: the PHY device
+ * @id: the PHY ID to be matched
+ *
+ * Compare the @phydev clause 22 ID with the provided @id and return true or
+ * false depending whether it matches, using the bound driver mask. The
+ * @phydev must be bound to a driver.
+ */
+static inline bool phydev_id_compare(struct phy_device *phydev, u32 id)
+{
+	return phy_id_compare(id, phydev->phy_id, phydev->drv->phy_id_mask);
+}
+
 /* A Structure for boards to register fixups with the PHY Lib */
 struct phy_fixup {
 	struct list_head list;